There is an urgent need for the development of vaginal microbicide that inhibit HIV transmission. An ideal antiHIV vaginal microbicide would inhibit viral infection from cell-free and cell-associated HIV with varying biologic properties, and be non-toxic for cells and vaginal and epithelium tissues. The overall objective of the project is to develop procedures to evaluate these anti-HIV properties of vaginal microbicide. Specific aims of the project are: a) To evaluate anti-HIV activity of topical microbicide against cell-free and cell-associated HIV in lymphocytes and T cell lines, b) To test the effect of environmental factors, such as low pH, semen, vaginal secretions on the anti-HIV activity of the vaginal microbicide, c) To examine the cytopathic effect of anti-HIV microbicide on the vaginal and cervical tissues using an organ culture system, d) To test the effect of microbicide on the transmission of HIV across the cervical tissue using an organ culture model. Such information will be extremely useful in development of vaginal microbicide that can prevent sexual transmission of HIV.